SAPORIN !?

Is there anyone out there who can help me?
I am a PhD student at The Institute of Psychiatry working on a selective mechanism
for removing cholinergic neurons from the basal forebrain in an attempt to model
Alzheimers Disease. I am using a new immunotoxin called Saporin. Thus far I have
carried out 3 pilot studies - to assess which dose removes the neurons but leaves no
other damage. Unfortunately Chemicon (the company which distributes the toxin) seem
to be having problems and keep changing both the concentration of the stock
solution, but more importantly the activity.
Is there anyone who is currently using this toxin successfully?
The dose that the company recommend I use are not accurate and even at 3 times this
dose there appears to be no effect.
Am I flogging a dead horse or can anyone help me!
Any comments or advise especially from anyone using this stuff would be much
appreciated.
Many thanks
TRACYANN (E-mail : spjutap at iop.bpmf.ac.uk)